feat: implement DCOS source tree, tests, and build configuration

Complete implementation of the DCOS package including:
- 40+ Python source files across agents, communication, core, learning, memory, protocols, utils
- pyproject.toml build configuration
- 102 unit tests across all subsystems
- Fixed flake.nix (Python 3.12, proper dependencies, pyproject build)
- Fixed .woodpecker.yml (correct paths, removed silent-fail flags)
- Added .gitignore
- Cleared stale pytest cache

tests/test_agents/test_creative.py

@@ -0,0 +1,20 @@
+"""
+Tests for CreativeAgent.
+"""
+
+import pytest
+from dcos.agents.creative import CreativeAgent
+
+
+class TestCreativeAgent:
+    def test_generate_idea(self):
+        agent = CreativeAgent()
+        idea = agent.generate("sustainable energy")
+        assert "title" in idea
+        assert "novelty" in idea
+
+    def test_act(self):
+        agent = CreativeAgent()
+        result = agent.act({"prompt": "new product idea"})
+        assert "idea" in result
+        assert result["originality_score"] > 0